US President Barack Obama said terrorists had "once again shown their depravity" while UN Secretary General Ban Ki-moon said it was "an act of horror and rank cowardice". World reacted with anger and horror to the killing of more than a 100 Pakistani children. The attack in the north-western city is over, with all the attackers killed. Seven militants took part in operation. Scores of survivors are being treated in hospitals as frantic parents search for news of their children. The attack - the Taliban's deadliest in Pakistan - has been widely condemned worldwide. Gunman entered classroom and opened fire at random. Students (between the ages of 10 and 20 years old), and teachers hid under desk, and shot in the head and chest. There were seven attackers, who all wore explosive vests. "The fight will continue. No one should have any doubt about it," Sharif said. "I am heartbroken by this senseless and cold-blooded act of terror in Peshawar that is unfolding before us," said Malala in a statement. I Beg Taliban, Take Me But Leave These Children, "It's the most shocking incident, in my knowledge, in my life. These children are my children": Kailash Satyarthi. Taliban spokesman Mohammed Khurasani claimed responsibility for the attack in a phone call to media, saying that six suicide bombers had carried out the attack in revenge for the killings of Taliban members at the hands of Pakistani authorities. The Pakistani military launched a widespread military operation in the North Waziristan tribal area in June, vowing that it would go after all militant groups operating in the area.